DO-AHEAD TIP: Toast slivered almonds.
Tear off 6 pieces of aluminum foil, each about 10-inches wide and the length of the foil box (just big enough in which to wrap the chicken rolls).
Preheat grill to MEDIUM.
In a food processor or blender, puree red bell pepper, toasted almonds, chopped green onion, garlic, salt and black pepper to the consistency of a pesto sauce (you may need to do this in batches, depending on the size of your blender or processor).
Place each chicken piece between two sheets of wax paper and, using a meat mallet or rolling pin, pound chicken to about 1/4-inch thickness.
Spread 2 tablespoons of pesto mixture on each chicken piece then evenly sprinkle with chopped basil and parsley. Starting at the smallest corner, roll the chicken pieces up tightly and place each on a foil square; bring 2 edges of the foil together and fold tightly over the chicken; fold the other 2 edges over the chicken.
Grill foil packages for 25 to 30 minutes or until chicken is cooked through.